Work machines, such as medium duty and heavy duty on-highway trucks, hydraulic excavators, wheel loaders, off-highway trucks and other heavy construction and mining machines, are used to perform many tasks. To effectively perform these tasks, a work machine requires a power source, such as an internal combustion engine. Internal combustion engines often include a housing, such as an engine block, and one or more working members, such as pistons. Typically, each working member is movably supported within the housing of the engine and separates a combustion chamber from a non-combustion chamber of the housing, such as a crankcase. Such engines combust fuel and air in the combustion chamber to produce power by driving the working member.
High pressure in the combustion chamber may drive combustion gases through spaces between the housing and the working member, into the non-combustion chamber. Undesirably high pressure in the non-combustion chamber may result. Additionally, combustion gases in the non-combustion chamber may contaminate and degrade oil in the non-combustion chamber. Furthermore, venting combustion gases from the non-combustion chamber directly to the atmosphere can have negative environmental consequences.
At least one internal combustion engine has been disclosed with provisions for venting combustion gases from the non-combustion chamber back into the combustion chamber. For example, U.S. Pat. No. 5,897,597 (“the '597 patent”) shows an internal combustion engine with a positive crankcase ventilation system. The positive crankcase ventilation system includes an outlet passage connected between a crankcase of the engine and an intake bore of the engine. Vacuum in an intake manifold of the internal combustion engine draws combustion gases out of the crankcase, into the intake bore, and then into the intake manifold for distribution to the engine cylinders.
Although the engine of the '597 patent draws combustion gases from the crankcase without admitting them directly into the atmosphere, the design includes disadvantages. The positive crankcase ventilation system of the '597 patent includes no provisions to prevent drawing oil and debris from the crankcase into the intake bore, the intake manifold, and the engine cylinders. Oil drawn from the crankcase into the intake bore, the intake manifold, and the engine cylinders can fowl the engine, causing poor performance. Debris drawn from the crankcase into the intake bore, the intake manifold, and the engine cylinders can accelerate engine wear and may even cause catastrophic engine failure.
The engine of the present disclosure solves one or more of the problems set forth above.